(1) Field of the Invention
The invention relates to a control circuit and dual touch control method for a four-wire resistive touch panel, and especially relates to a four-wire resistive touch panel with a double-touch pattern capable of determining gesture of scrolling page, zooming page or rotating page.
(2) Description of the Prior Art
With the technological evolution, the rapid development of human-machine interface is from traditional keyboard and mouse to touch screen or touch panel, which seems to gradually dominate the market. Currently, two primary touch panels are resistive touch panel and capacitive touch panel. Resistive touch panel has features of light weight, thin thickness, less power consumption and being ably operated with a finger, stylus or just about any pointed object but less bright while conversely capacitive touch panel has features of more bright but it must be operated by finger but not an ordinary plastic stylus. Because marketing trend is apt to slim and light trend with energy saving demand, the resistive touch panel is more competitive than the capacitive touch panel in current market.
Currently, resistive technology of touch panel is most popular due to least manufacturing cost. Owing to least manufacturing cost, the most popular of touch panel technology is resistive type, which is mainly classified into two categories, which are four-wire resistive kind and region-segmenting resistive kind. Typically, four-wire resistive touch panel mainly comprises an upper active conducting layer and a lower active conducting layer with insulated spacer layer sandwiched therebetween. When a finger presses down on a point on panel's outer surface, the upper conducting layer and the lower conducting layer become connected at that point so that the touching point is computed by the touch panel, and then is converted into a coordinate value. By means of the coordinate value, a finger touching gesture is determined. However, the gesture of finger operation of conventional four-wire resistive touch panel is confined in single touch capability only, which can not conform to the market requirements.
For meeting the increasing requirements of complicatedly competitive market recently, the improvement of the touch panel is from single-touch to multi-touch function which defines diverse of hand gestures to input, commands, and the advancement of conventional four-wire resistive touch panel is region-segmenting resistive touch panel, which is able to provide adaptable multi-touch function. The technological rationale of the region-segmenting resistive touch panel is that a major touch panel is divided into multiple zones such that each zone is equivalent to a minor four-wire resistive touch panel with a single touch capability respectively. Thereby, the multiple zones of the major touch panel can substantially provide multi-touch function by aggregating overall single touch capabilities of all multiple zones. However, there are two inherent vulnerable drawbacks, which are delicate connecting wire and uneven resistance distribution. For delicate connecting wire, most wires connecting between upper conducting layer and lower conducting layer are made of silver, which are easily breakable in void. For uneven resistance distribution, the properties of divided zone are different from zone to zone and liable to cause uneven resistance distribution with incurred Newton rings so that not only the yield is decreased but also the manufacturing is increased.
Therefore, how to solve improved four-wire resistive touch panel to have multi-touch function with diverse of hand gestures and to obviate all inherent vulnerable drawbacks of region-segmenting resistive touch panel becomes an urgent problem in the technical field of the present invention.